Computer Components Flashcards
When was first general-purpose electronic digital computer made
1940
What was the old computer program
Data. ->. Hardwired program. ->. Result
What is the stored program concept
In 1946 a scientist by the name of John von Neumann realised that the programming
process could be made much more efficient if the program could be stored in the
computer’s memory along with the data. This idea is known as the stored-program
concept. The basic design that allows it to happen is known as the von Neumann
architecture, and is the basis for nearly all digital computers.
The main features of architecture are :
Main memory: store both data and instructions
Central processing unit, comprising of :
- Arithmetic Logic Uni (ALU) capable of operating on binary data
- control unit, interpreting the instructions in memory and cause the m to be executed
I/O
equipment operated by the control unit
Advantage of this it that hardware does not need to re wire the hardware
What does CPU stand for
The central processing unit
What are three institutions to operate the computer
Fetch = the next instructions is fetched from main memory
Decode = produces signal that control the other part of the computer such as the ALU
Execute = the instruction is executed
What are the two types of operations on data the ALU performs
Arithmetic = + - / X
Logical operatorss = comparing one data item with another, determining if the first data item is smaller, equal or greater than the second data item
CPU HIGH SPEED MEMORY
Contains height speed memory used to store temporary results and control information. The memory is made up of a number register, with each register holds one number
Two main features to determine CPU performance
- clock speed = CPU has an internal clock that generates a regularly timed pulse. All processor activities must begin with clock pulse. Some activities may take longer than clock pulse. Clock pulse rate is measured in Hertz (Hz). Computers today have 4GHz (4000 mil cycle per second) the higher the speed the faster it operates.
-cell size = the number of bits that the CPU process simultaneously. Bits are grouped into 8, 16, 32, 64, 128 bit words, And processed as a unit during input and output, arithmetic and logical instructions. More bits mean bigger cell size, meaning it operates faster.
Main memory
Consists of we of locations, defined by sequentially numbered addresses. Within this memory both data and instructions can be stored.
Number of bytes in main memory refers to as the computer memory size.
What does Ram stand for
Random access memory
What does rom stand for
Read only memory
Two types of main memory
RAM = used for store and running applications and data that is being processed. This is volatile, meaning that it loses all its content as soon as the machine is switched off.
ROM= it’s non volatile, so content is permanently etched into the memory chip at the time of manufacturing. It is used to hold the bootstrap loader,, which is the program that runs as soon as the computer is switched on and instructs it to load the operating systems from disk to main memory
Cache memory
A type of very fast memory, used to improve the speed of a computer. Acts as intermediate store between the CPU and main memory. Works by storing the most frequently or recently used instructions and data so that it will be very fast to retrieve them . So when an item of data is needed, a whole block of data will be read into the cache in the expectation that the next piece of data required is likely to be in the same block .
Secondary storage
Ram is primary
Secondary storage is non volatile.
Magnetic media and optical media are what is known as secondary storage.
Most common example is disk.
All computers come equipped with an in built hard disk , with capacity measured in bytes , can store tens of gigabytes and used for storing applications, data for long term storage and operating system.
